The Cavendish Experiment - Sixty Symbols
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- Опубліковано 5 лип 2011
- Henry Cavendish was an unusual man but also one of the first great scientists. Many of his discoveries remained hidden in his notebooks, but his name is still attached to the the extraordinary Cavendish Experiment.
With Roger Bowley
More physics at www.sixtysymbols.com/ - Наука та технологія
"measured the current by the degree of agony"
I propose a new unit for electric current: 1 A = 1 Agony.
Call it "Oscillating Watts" abbreviated as "OW"!
1 A = 1 AAAAAAAAAAAAAAAAAAAAARRRRRRRRRGGGGGH
9 years late to the punch
I know im asking randomly but does any of you know of a method to log back into an instagram account?
I somehow lost my account password. I would appreciate any assistance you can give me!
@Kolton Santana Instablaster :)
If you've ever "measured" the typical house current in the U.S. you have felt all 60 Hertz! OW!OW!OW!OW!...
Measuring electrical current with an owmeter...
"He barely talked to anyone in his 3 years of study in Cambridge. If you wanted to ask/tell him something, you'd have to go outside the door of the room he was in and ask the question to the room."
I don't think I've ever related to anyone more than this guy
But he was successful :)
...successful at dropping acid(s) at school!
The fact you relate to him makes you quite the opposite.
@@noggix3313 Cavendish was pathologically shy, not autistic or a sociopath.
So the first ammeter was Henry Cavendish.
Or some unfortunate caveman who was struck by lightning
I loved doing the Cavendish experiment in undergrad. Actually seeing gravity work between two non-astronomical objects blew my mind.
yes when I realised this experiment had been done my entire idea of gravity changed.... as related to the mathematics... It;s so precise
Oh wow. You've proven gravity?.. I smell BS.
I measured the speed of light with a mirror spinning at 1000 Hz and a laser reflecting off a mirror 15m away into a microscope and got 3x10^8 m/s. I was so overawed to have physically measured light. I would imagine the same happening when measuring G.
@@idjlesWow, can you give more details?
@@kevindouglas8768you flat earths can’t even explain the sunrise and sunset 😂 and you have the audacity to comment on the big boy science. You can’t even explain why a sun rises, goes across the sky, and sets with the exact same angular diameter and speed. And that’s just the start of the problem. The stars spin in opposite directions looking at each pole, the image of the moon is flipped for observers in each hemisphere, and if you try and explain where the southern star is on your map, it’s outwards for observers in the southern hemisphere, when this star does not move. This is scraping the bottom of the barrel on conspiracy theories
Man, the most recent comments on this video are quite worrying.
Ingenious introvert scientist!
Usaid Khan sounds more like he had anxiety issues. I would probably do the same in his situation and i'm outroverted.
+Bluestrawberry Actually the adjective is extroverted; the opposite being notenoughtroverted
+mrbaggy dave I'm just going to type introvert
Watch the video again he tells you how he's wrong and crazy... his experiments that prove gravity are not repeatable
Yes They are repeatble. You can do it your self.
Yay, I can't say it enough, thanks for another great video Brady!! I sincerely wish from the bottom of my heart more people like you around the would would take their time and make videos like this, and dedicate themselves to openly sharing scientific knowledge in a user-friendly, but still informative way!! I'd take in a few videos like this every day, and I think I'd still crave more!
Did this experiment at University, it's pretty amazing!
I actually did the Cavendish experiment today with exactly the same instrument at my university! I came to the conclution that the Big G is approximately 6.792e-11N(m/kg)^2(not to bad considering the cruel means of measuring by eye), this experiment was both very intresting and educative. Highly recomended!
MOAR!! Thanks for these videos :D Love watching them
Thank you! What a great video! Such a quirky, fascinating genius this Cavendish!
"he measured the current by the degree of agony he felt" now that's dedication! :)
Surfing On Squarewaves I like how he proved that gas wasn't flammable by blowing it on a candle and blowing up in his face. This has to be a troll video.. why is he a genius because he came up with something nobody can repeat
Surfing On Squarewaves Hmmm, No, That's Mentality Challenged!🤔 Considering the rest of his antics, he most definitely had a disorder! But, Being delusional enough to believe hydrogen and oxygen makes water, then convincing everybody else to believe it, is a talent.
@@somewhatinformed716 It's been repeated thousands of times you insufferable mouth breather. Why are flat-earthers incapable of telling the truth?
Also, you don't know the meaning of the word "inflammable" as Cavendish was using it.
I've posted a couple of video responses from the FavScientist channel which I also run... nice anecdotes about scientists much like this video!
This is such an awesome channel!! Keep up the great vids!
I wonder why measuring the subjective agony of experienced electric current never made it into the SI-system...
As a pain researcher I've basically tried this. While the correlation between the applied current and the perceived pain is ok (pain reliably increases with higher current), the noise in the data is enormous as peoples individual perceptions of pain varies hugely. We'd need to train up some SI approved human ammetres to have any hope of a reliable measurement across time and location.
@@psychalogy What unit is this measured in..."agonies"?
@Ed we use pain rating scales. They basically ask people to rate their perceived pain from zero (no pain) to either 10 or 100 (worst pain imaginable). Which one you use depends on whether you’re using an NRS 11 (Nociceptive Rating Scale - 11 graduations) or an NRS 101 pain rating system.
Assigning units is tricky as a unit assumes that the scale proceeds linearly i.e. the difference between 1 and 2 is the same amount of difference between 9 and 10. However this doesn’t seem to be the case, the underlying construct of pain can be decidedly non linear.
Ouchshitz!
Oh, I love all the videos Brady puts up!
Nice to see a video from sixtysymbols!! thanks!!
Thank you for explaining the torsion experiment! I have always wondered how it was done, and at 1800's no less!
Late 1700s, I think.
This is absolutely amazing!
Incredible. Thank you for the video.
I thoroughly enjoy every single video that 'Sixty Symbols' or 'Nottingham Science' produce!!!
Fascinating guy, thanks for the video.
Lovely story. Well told!
The most hard core introvert ever ❤
Historically, some of these scientists were obsessed with knowledge. Driven to solve problems with patience and determination that seems to be lacking in the modern world. I could be wrong. Maybe there's something unhealthy with that kind of obsession, and we don't hear about it anymore. Modern collaborative efforts probably have replaced the "If you want something done right...." approach. It's very inspiring to learn about how determined an individual can be during a period when so many questions were everywhere. It's as if they didn't have any reason to believe that they might not find an answer. Great video! Thank you very much! It's extremely important for people to learn about the history of the scientific endeavors that changed the world. Often, it's just as interesting as the science itself. I try to explain to some of my sceptical friends that these people sought knowledge for all of us. They genuinely were trying to make life better for future generations of the human race, and that's why they tried so hard.
Brilliant! Very interesting. Didn't know about this
@SheBlindedMeWScience thanks, i actually watched his 45 part lecture on unified field theory. Its compelling watching I will admit, and raises some thought provoking points, but i cant help thinking the way he leaps from supposition to supposition is very wild and incoherrent.
Cavendish was the original boss. I loved reading about this experiment in particular for how difficult it is to do properly, and hearing about how he would dangerously test on himself.
Great video!
How could anybody 'dislike' this video?! Once again, thank you to the wonderful faculty at The University of Nottingham!!
Whew, that was impressive. That is a very impressive list of discoveries for one person, too bad he was so asocial that he didn't tell anyone. Wonder what he could have accomplished if he'd worked with others.
@mozad655 To minimize the gravitational pull from any mass outside the instrument we measured the angle by using a light directed towards a mirror on the torsion pendulum. by standing approximately 6 meters from the measuring device we could measure the reflected lightbeam and thereby measuring the time of oscillation to calculate the equilibrium point, where the force of gravity is equal to the force from the torsion pendulum. I have no idea where the university received the instrument
Great video. Thank you. :)
Fantastic!
@dezent Professor Bowley said the exact same thing (though it is not in this final cut)
Cavendish sounds oddly fantastic.
i went to henry cavendish primary school in balham. i've always wanted to know more about henry cavendish, all i knew was that he measured the weight of the earth. thank you sixty symbols ! was extremely interesting (:
I love this guy.
Thank you. I'm very attached to it as well.
This video is the reason I passed my Physics A-Level
Thank you so much for making these amazing videos!
would love to see you guys do one on what existed before the big bang
Wow...I wonder why I haven't heard about Cavendish, well...I heard his name and might have heard it vaguely said what he did, but I didn't know how strange he was...
Super Experiment 👌👌👌
I paused the video before he said "don't try this at home" and now I don't have a face.
William Horn...hey, at least now you might get some compliments on your looks. 😒
@@dross4207 Well played...
@@dross4207 😂😂😂
He sounds strange. Kind of reminds me of the stories about Pythagoras.
our professor actually did this experiment in a lecture, it took ages to get a useful amount of data
Great video. Cavebdish sounds like a strange man but I still think Paul Dirac is the strangest of the strange.
'He was a very strange man' That amused me very much :)
fascinating
@Xerotaerg nono. What was said is that even through he was really rich, he went to study natural sciences at Cambridge.
number 1 school in the world...at the time
For now you can watch khanacademy and many more youtube videos, wikipedia etc. Take notes. It will really help you understand the subject.
Professor Emeritus Roger Bowley is brilliant. It's very sad he's no longer frequently featured on Sixty Symbols.
+Saul McShane He retired. There is a video about it called 'A retiring Professor'.
I have to correct something in this old video. It is true that Cavendish was the first person who made hydrogen. However, it wasn't him who filled his mouth with it and blew it into a fire. That was the French chemist Pilatre de Rozier.
I just read that in a Bill Bryson book
amazing
2:12 "he invented hydrogen".
What an amazing fellow. I use hydrogen based chemicals everyday.
JNCressey
Of course he means “discovered”
@@Dalonghair 🙃
hahaha, what an underrated comment. I had the same thought as you, when he said it.
How did friction not stop the experiment from working? was it levitated by magnets or something?
@454ffv I also noted the similarity and wondered if the character was based on knowledge of Cavendish's personality.
@vertexgo
The real reason is that today you'd have to compare it to something like the LHC.
Comparatively, it's not very technical, though nonetheless clever.
Lord Cavendish really is one of the most interesting scientists.. his intelligence only matched by his ... uniqueness.
@TerenceHorsman You can use google and find out in about 30 seconds. Liquid helium is a good starting point.
This is something that would be neat for a physics class to set up on day one and check on periodically.
@TerenceHorsman Superfluidity is a state of matter in which the matter behaves like a fluid without viscosity and with infinite thermal conductivity.
more on wikipedia :D
current should be measured in "ouches".
@odaymustdie are you sure they are lead? Have you tried putting something heavy on them to see if they would be squashed? Perhaps we should set up an experiment..
the guy had balls!
@headmase any particular one? he seems to have many!
@clayphish Do you also answer the room ?
i'd love to know
1. what cavendish thought when he discovered the density of the earth was much more than the density of ordinary rock.. surely this was surprising?
2. how big G is measured nowadays to much greater accuracy
maybe another video?
Sadie Smith
It was already expected from previous experiments on the gravity of mountains that the average density would be higher than that of ordinary rocks, which are mostly about 3 x the density of water. The mountain experiments suggested an density of about 4 x water, while Cavendish found about 5.5 x water. I'm not sure I'd call that *much* more than ordinary rock - it's not like it was a factor of ten. I don't think scientists were hugely surprised, because they expected the density to increase with depth. I don't know when they first suspected the Earth had a metallic core, but it might have been guessed from the fact that the Earth has magnetism.
DavidB5501 so it is strange then that when a magnet is heated up it loses its magnetism.
@@FireFirePow The Earth's magnetic field isn't like a bar magnet. I have no idea why you would even think that is applicable. Do you not believe that temperature rises as you go deeper into the Earth? Do you not believe the Earth has a magnetic field? The Earth's magnetic field is basically an electromagnetic effect (have you heard of electromagnets?), believed (yes, science is still working on the details) to be caused by the Earths core acting as a dynamo (have you heard of dynamos?). So nothing strange about it. If you answered no to any of those questions, you have some research to do. And as we know, learning new things is fun.
@@daveg2104 uhm, wat? can you first of all prove that the Earth even has a molten magnetic core producing a magnetic field? like, do you have any pictures of this, hard evidence?
what about the layers of the Earth we've been seeing plastered in school textbooks all over the world? is there any evidence for that because as far as I know the deepest men have ever bored is 7.5 miles... so... there is literally ZERO proof of ANYTHING below that depth all that was found is that it got hotter the deeper you went, this hardly is enough to base a molten magnetic core on.. of course it gets hotter the deeper you go.. duhh more heat is trapped!
so to answer your various questions, no I do not believe it all and I think that's perfectly reasonable seeing as I have NO REASON to believe that hogwash
@@FireFirePow What's with the "uhm, wat" sic. You are an expert, learned in this field are you? If you don't know, just admit you don't know, there is no shame in that. If you want to know, there are plenty of ways to find the answers. But do you want to hear those answers? The choice is yours, but I'm not playing your silly pigeon chess game. Have a nice life.
thanks,yes i do love khanacademy and have been using it for past 3 years, but now since i am studying advance subjects in physics (hamiltonian and lagragians, qed and stuff) khan is no more that useful, i would have loved to go to Nottingham :)
@vertexgo Because today there are mechanical crane that could set all this up while back in the days it was all man-power. Hence why it was very technical for that time.
Can anyone point me to where this experiment is carried out regularly or recently?
***** yes most high schools/unis will do it. I meant high end under very robust/controlled conditions.
Why did he not mention John Michell, who designed and built the apparatus?
…..it’s simple: John Michell was black!!
@DeepGrey1A Just sounds like Extreme Anxiety, and the only way he could get around it was to not do the things he knows triggered it.
imagine how much futher we would have been if he had been able to publish his research
Cavendish, my kind of guy.
Could you guys please explain the Galilean cannon?
this professor is brilliant!!! i wanna study physics from him but don't have enough money :(
@noxure I did not mean to say that--- I was about to say that he invented the hydrogen balloon, but he didn't so I stopped myself from saying that and ended up mis-speaking, if that is the word I am looking for.
Cavendish is one of my favorite sciences ever!
He was a fraud
This professor told me in class that "A scientist looks for the Truth". I will never forget about that.
And all this in 1798, that's impressive!
@TerenceHorsman Anything to do with quicksilver? I'm not top noch expert on the subject.
SCIENCE TIME YEEEEAAAAHH!
@nemesis80008 Check out Nassim Haramein on that, he gives good optics on the subject.
Begins to illustrate the experiment at 3:30
@jandkas
A mix of all of them :)
And you can see Pluto on the chart of planets!
I have to be honest, i thought this was going to be about bananas...
+Steven Davidson Very close. The Cavendish family is a large and prestigious one and one of Henry Cavendish's relatives, William Cavendish, I believe, was the person that the Cavendish banana is named after. A quick Google search will tell you more than I can at the moment (whether William was the person who cultivated that type of banana, or whether it is just named for him), but it is interesting reading.
same here
Don't you dare call your self stupid ever again! You're a sciency bad-ass and don't you ever let anyone tell you otherwise (your self included)!
"Do I attract you physically?" - Feynman
There needs to be a movie about this guy. He was amazing. A great autistic scientist.
@ikacakazuma1 I am very flattered to be compared to Richard Feynman --- but he did not have the good fortune to be filmed and edited by Brady Haran. He left out lots of stuff about how money from the Duke of Devonshire given to Cambridge University to honour Cavendish's name, and a list of the Cavendish professors.
Great man... only if he would have published his theories...
Small note... Clapham Common is definitely not a poor area of London, not now nor ten years ago.
I have a question, first I would like to thank you for taking the time to make this video, I find all your videos enlightening.
My question is at minute 5:37 in this video; when you say "gravitational constant", you mean the constant at the earth's surface est. 9.8 m/s^2?
Also, can you direct me some where to find out more information about how the; measuring of the angle in the small mirror, you can figure the gravity? ( Truly fascinating )
thank you very much, it is never to late :)
Joseph DiDonato Thank you very much. So he solved the "g" from T=2Pi (L/g)^1/2 equation.
+Mark Lares 9,8 m/s^2 is the average gravitational acceleration at the earth's surface and the same as the "g" in the pendulum formula, but it's not the same "G" as Cavendish found. you can calculate "g" with "G", the mass (M) of the earth and the radius of the earth (r): g = G * M / r^2 = 6.67*10^-11 * 5.97*10^24 / (6.378*10^6)^2 = 9.79 m/s^2. "g" depends on the place on earth. The radius isn't the same everywhere.
When two objects are attracted to each other in space they begin to move towards each other. However, how does one work out their velocities? The closer they get the faster they travel. But how fast, and how could you calculate it? Please help I am trying to write a program that simulates such things!
+Celtic Saint You can measure the acceleration. By the way; acceleration increases too, when the objects get closer. It may be that you need integral- and differential-calculus for this.
september1683
Thanks I'll look into that.
But the force due to gravity by the earth eventually causes the ball to move back. What is happening with the ball is harmonic oscillation (since it was a pendulum of small angles). He was able to measure the period of oscillation.
I did the calculations myself and found that the acceleration you want measured is not needed to calculate the gravitational constant.
you can do it mathematecally, the F ORCE of attraction yields an accelration on kilogram masses....thier is an ocsilation of frequency resonance, it can be ignored somewhat, the force is 1/radius^2 which is changing instantaneously, did your program work?
Hats off to Brady and the University of Nottingham faculty! That would have been more appropriate for me to say : )
He were very clever